Histological Spectrum of Urinary Bladder Biopsies with Special Emphasis on Unusual Non-urothelial Tumours

Urinary bladder carcinoma accounts for 3% of overall cancer deaths worldwide. Low-grade urothelial carcinomas are the commonest of the bladder tumours followed by high-grade urothelial tumours. Non-urothelial tumours account for less than 5% of bladder tumours and frequently present a diagnostic and therapeutic challenge. The common non-urothelial neoplasms seen in other reports are squamous cell carcinoma, adenocarcinoma, and neuroendocrine tumours. The present study enumerates the types of urinary bladder tumours seen in our centre in a span of 7 years with their clinical, histology, and immunohistochemistry findings, emphasising the findings of seven types of non-urothelial tumours few of which were very unusual. These include inflammatory myofibroblastic tumour, mature teratoma, angiomyofibroblastoma, metastatic carcinoma from prostate, primitive neuroectodermal tumour, and squamous cell carcinoma. Angiomyofibroblastoma in our series is the first reported case seen in urinary bladder. It is important to identify these uncommon tumours as few of them may behave more aggressively than urothelial neoplasms, have poorer prognosis, and are often diagnosed in late stage.